Build your thermo scale

Do you want to know more about thermometers?

Well check this

Thermometers

Developed during the 16th and 17th centuries, a thermometer (from the temperature gradient using a variety of different principles. A thermometer has two important elements: the temperature sensor (e.g. the bulb on a mercury thermometer) in which some physical change occurs with temperature, plus some means of converting this physical change into a numerical value (e.g. the scale on a mercury thermometer).

Read more in Wikipedia.

Farenheit Scale

Daniel Gabriel Fahrenheit (1686–1736). Within this scale, the freezing of United States, Belize.

Read more in Wikipedia.

Celsius Scale

Celsius is a scale and Anders Celsius (1701–1744), who developed a similar temperature scale two years before his death. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature uncertainty. The unit was known until 1948 as "centigrade" from the Latin "centum" translated as 100 and "gradus" translated as "steps".

Credit: uoregon.edu

From 1744 until 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one VSMOW (specially-purified water). This definition also precisely relates the Celsius scale to the thermodynamic temperature with symbol K. Absolute zero, the lowest temperature possible at which matter reaches minimum entropy, is defined as being precisely 0 K and −273.15 °C. The temperature of the triple point of water is defined as precisely 273.16 K and 0.01 °C.

This definition fixes the magnitude of both the degree Celsius and the kelvin as precisely 1 part in 273.16 (approximately 0.00366) of the difference between absolute zero and the triple point of water. Thus, it sets the magnitude of one degree Celsius and that of one kelvin as exactly the same. Additionally, it establishes the difference between the two scales' null points as being precisely 273.15 degrees Celsius (−273.15 °C = 0 K and 0 °C = 273.15 K).

Read more in Wikipedia.

Rankine Scale

Rankine is a physicistKelvin scale was first proposed in 1848.)

The symbol for degrees Rankine is R^{absolute zero, but the Rankine degree is defined as equal to one degreeCelsius used by the Kelvin scale. A temperature of −459.67 °F is exactly equal to 0 R.}

Some engineering fields in the National Institute of Standards and Technology does not recommend using degrees Rankine in NIST publications.

Read more in Wikipedia.

Another temperature scales:

The Rømer Scale.

And here is the conversion formulae:

Dark energy interacting with dark matter

Notes on dark energy interacting with dark matter and unparticle in loop quantum cosmology

Muneer A. Rashid

(Submitted on 8 Jul 2011 (v1), last revised 29 Jul 2011 (this version, v2))

We investigate the behavior of dark energy interacting with dark matter and unparticle in the framework of loop quantum cosmology. In four toy models, we study the interaction between the cosmic components by choosing different coupling functions representing the interaction. We found that there are only two attractor solutions namely dark energy dominated and dark matter dominated Universe. The other two models are unstable, as they predict either a dark energy filled Universe or one completely devoid of it.

Notes on dark energy interacting with dark matter and unparticle in loop quantum cosmology. (arXiv:1107.1558v1 [physics.gen-ph])

Optical Force Measurement. Credit: eecs.northwestern.edu

"(PhysOrg.com) -- Researchers from the NIST Center for Nanoscale Science and Technology and the University of British Columbia have shown that the interaction between a light pulse and a light-absorbing object, including the momentum transfer and resulting movement of the object, can be calculated for any positive index of refraction using a few, well-established physical principles combined with a new model for mass transfer from light to matter."

Electromagnetic radiation, like light, carries momentum and can transfer its momentum to matter via controversy over the correct form of the electromagnetic momentum density in matter.

There was two forms:

•  In the “Minkowski formulation,” the momentum density is proportional to the index of refraction;
• in direct contrast, the “Abraham formulation” finds it to be inversely proportional. 

And the two equations for the momentum in a dielectric with refractive index n are:

• The Minkowski version:

• The Abraham version:

where h is the speed of light in vacuum.

In 2011, an optical experiment was performed to study this problem based on Lorentz transformation should be replaced by c/n to describe electrodynamic phenomena in a dielectric medium^[1] Consequently, the momentum of a photon in vacuum is p=E/c and the value should be p=E/(c/n)=nE/c in media, although it is not measured directly.^[2] It is asserted, that this confirms Minkowski's formulation.

[1] Wang Zhong-Yue, Wang Pin-Yu, Xu Yan-Rong (2011). "Crucial experiment to resolve Abraham-Minkowski Controversy". Optik 122 (22): 1994–1996. 10.1016/j.ijleo.2010.12.018

[2] Wang, Zhong-Yue. Graphene, neutrino mass and oscillation. /0909.1856

The recently published in Applied Physics support the Abraham formulation: Revisiting the Balazs thought experiment in the presence of loss: electromagnetic-pulse-induced displacement of a positive-index slab having arbitrary complex permittivity and permeability, K. J. Chau and H. J. Lezec, Applied Physics A 105, 267-281 (2011).

"The researchers propose a set of postulates for light-matter interaction that encompass: a) the Maxwell equations, which govern classical electromagnetic behavior; b) a generalized Lorentz force law, which describes the force felt by matter in the presence of an electromagnetic field; c) a model for electromagnetic mass density transfer to an absorbing medium; and d) the Abraham formulation of momentum density. Using both closed-form calculations and numerical simulations of the interaction between an electromagnetic pulse and a test slab, the researchers demonstrated that their postulates yield results that are consistent with conservation of energy, mass, momentum, and center-of-mass velocity at all times." ( PhysOrg)

Read entire article in PhysOrg

Andrew Fraknoi made a catalog with Astronomy applications for your mobile and you can found it here (most applications is for iPhone).

Now I going to leave here my modest listAndroid applications:

The Google SkyMap let you observe the sky at night. To do that you must install the free application from Android Market. Open the application and point your mobile to the night sky, then you'll see in the mobile screen all the information about the star or other sky object that you are observing.

The Zenit Mobile Telescope is an application that isn't free and made almost the same task as Google SkyMap, it seems that has more information and best image resolution.

The eufisica is a free application with news about Physics and Astronomy. Is still at an early stage, but already has some downloads.

The Android Market you will find many NASA applications (some are official and free, others are not).

The Solar System Explorer Lite is a interactive 3D journey in the Solar System. It has planets, moons, asteroids and space probes.

The Exoplanet Explorer Lite is a journey to the deep space. It is based on latest available data. Explore 3D recreations in more than 500 known planets and systems.

I forgot to publish my postal card this year. :(

But, here it is. :)

Best wishes to all.

JG

How Differential Steering Works

"Steering is the term applied to the collection of components, linkages, etc. which will allow a vehicle (rail transport by which railroad switches (and also known as 'points' in British English) provide the steering function."

in wikipedia


G. W. Lucas has the equations for an elementary trajectory model for the differential steering system of robot wheel actuators. Check his this one for the java applet.

Discovery, Innovation and New Destinations Highlight "This Year @NASA"

Kepler's Birthday

Johannes Kepler (December 27, 1571 – November 15, 1630) is not a name that most people recognize, but if you are aware of the recent discoveries of new planets, will recognize that many Kepler 22b, the first planet discovered in the habitable zone of a star, an earth possible planet like ours.

of planetary motion still apply today, and enabled Newton to give us the of universal gravitation.
In 1596, Kepler published Mysterium Cosmographicum, where he set out arguments for the heliocentric hypothesis.
In 1609 published three laws of planetary motion that now bear his name:

• The planets describe elliptical orbits with the sun at one focus.
• The radius vector connecting the planet to the sun describes equal areas in equal times. (law of areas)
• The squares of the periods of revolution (T) are proportional to the cubes of mean distances (a) from the Sun to the planets. T² = k a³, where k is a proportionality constant.

Probably most of us will never use this information in our life, but it does well to remember that those was important intellectual achievements of Western civilization. We could even think to remember Kepler itself and its laws would be enough, but Kepler had more projects, for example, projects of the first glasses for myopia and hyperopia.

Watch this video with a simulation of Planet and Star size comparison:

The video from Discovery:

Let's break the speed of light in your backyard :)

Higgs boson still missing, but we have new particle

Credit: CERN

Scientists still looking for the Higgs Boson, and they have just found the LHC's first new particle: Chi-b 3P.

It's actually told to BBC:

"The better we understand the strong force, the more we understand a large part of the data that we see, which is quite often the background to the more exciting things we are looking for, like the Higgs. So, it's helping put together that basic understanding that we have and need to do the new physics."

More in Gizmodo.

Want to know more about Higgs boson? Watch this video: